Ladder



J. W. PEASE July 27, 1943.

LADDER Filed July 22, 1942 a ented July 27, 1943 H -LADDERJ Pease, Rochester, s assassin jury 2'2, 1e42, Serial No. stress e1am c1.2aa any present invention-relates to ladders andvit has for its object to provide an inexpensive, simple and efficient means ior fortiiying the connections or the rungs'steps treads thereof with the side rails, whereby loosening of the-former and resulting weaving of the ladder structure as a whole will be obviated thr ougho'utthe normal useful life of such a product; More particularly, the in'ven tion is concerned with a provision whereby in'the hand assembly of ladders thesaid rungs, steps or treads will. be squeezed or clamped with great force between'the side rails rendering these parts relatively immovable for a long periodand all "without the useof any special assembling-ap paratus. In .acoomplislnng this-,-.my invention contemplates employing a combination strut and tie which, during fabrication, isautomat'ically mutilated when it is tightened in away that looks it in its ultimate position under stresses that preclude the possibility of it resuming. the

Figure 1 is a side elevation of a step-ladder con structed in accordance with'a-nd illustrating one ezn-bodirnent ofmyinvention;

Figure 2 is a front view thereof .r 5- Figu'relfi is anenlarged fragmentary vertical section taken in a plane extending longitudinally of one of thesteps or treads and substantially longitudinally of the supporting side rails;

Figure 4 is a further enlarged fragmentary do tail of the showing of Figure 3 with the parts in further section; I l

Figure 5 is a detail fragmentary section similar to Figure l taken on the line 5-5 of Figure 4 and Figure 6 is a bottom plan view of the detail of Figures 4 and 5.

Similar reference numerals throughout the several views indicate the same parts.

I have shown and will describe my invention or the purpose of this application as applied to the construction of a step ladder in which con- 7 stroy tight contactwith the tread ends. Qnce. :10

types of ladders; The accepted practice'in the making of .step' ladders is' to confine and support-flat and rectangular stepsor treads between side rails in whiohtheir ends are mortised or supported by cleats on the inside ofthe rails. The treads'thlls resisticompression-of the rails but it is important to find a fastening means to resist tendenoi'esof the rails to spread and dethis loosenessdevelops and theladder's'tarts to weave, it fractures the structure of. the fibres of both wooden elements l and gradually destroys their fit so that the condition grows progressively worse, In the practice of my invention Laccurately fit the. squared endsof the treads in square mortises in the rails and then hold them pressed together so tightly that relative ,movement and the tendency toweave is stopped before it starts.

Referring 'rnore particularly to the drawing,

there is thcreilldstrateda conventional folding type of sjtepladder comprisingthe ladder proper A, brace]; hinged thereto at Dlwith an approseats fitting including the top and interme-. 'diate folding braces" E pivoted to bothelements.

The interior faces ofthe side rails l of theladd'er proper A have straight shallow mortises 2 receivmg the square ends of the flat treads 2. For

preliminary assembly purposes the treads are fixed in position by nails dwhioh also'permanentl y se'rve to iurtherprevent thetre'acls from slipping longitudinally of the inortise'salthough, as will hereinafter appear, they are hardly necessary for this purpose. A short distance below each tread 3 I bore the side rails at 5 and insert therethrough a straight, or substantially straight, steel rod 6 theoriginal condition and position of which is indicated by dotted lines in Figure 3. 'These are in the nature of bolts; The

head 1 thereof at one end inv each instance is provided with a washer 8 that bears against the outer faceof one side rail while a I1ut'9 at the other threaded end through a similar washer It bears against the outer face of the other side rail. The rod or bolt is secured in this position with reasonable tightness according to the distance of the bores 5 from the underside of the tread.

The rod is first run through an eye in the flattened head ii of a bolt I2, the threaded shank of which extends vertically through a hole in the center of the tread, which hole is counterhored at is from above to accommodate a washer I4 beneath a nut it. The bolt is also provided on the underside of the tread with a washer l5 engaged by the shoulder of the head I l as shown in dotted lines in Figure 3. The shank of the bolt l2is originally longer than is shown by full lines in the drawing to permit the insertion of the washer l4 and the nut l5 thereon in the counterbore 13. As the nut is tightened it bends the rod 6 upwardly at the center until the washer i6 is compressed between; it and the underside of the tread 3. Not only this, but the'tightening'of the nut is continued until a portion of the rod is locally further distorted and actually drawn into the opening I! in washer I6. This opening is considerably larger than the bolt head and its inner margins are preferably left with sharp corners or burrs which, with the pressure generated by the nut, actually out into or dent the rod. Between such abutments, the

7 portion of the rod that is within the bolt head the'underside of the rod 6 to maintain this tenv 'sile strain. 7

Finally the projecting threaded ends of the bolt l2 are sheared off level with'the upper surfaces of the tread and are preferably upset or riveted over on the nuts l5 to lock them against loosening. r

The fibres in the internal structure of the connected wood parts i and 3 are, of course, slightly compressible, but they also react with a correspending sustained expansive force that holds all ofthe material connections in extremely tight contact where theoriginal compressive force of the rod and bolt'action is exerted. Such isthe case in the matter of the grain ends of the treads crow'ding'the mortises of the rails and withthr. treads acting as struts and the rods themselves acting as practically independent ties, a triangulation of forces is created that prevents the treads from even starting to loosen and hence holds the ladder as a whole rigidly-against the weaving first mentioned in this application.

The rod can thereafter not I claim as my invention:

1. In a ladder, the combination with a pair of side rails and an abutting tread therebetween having its ends supported thereby and acting as a strut, of a tie rod extending through both side rails below the tread to react compressibly at its ends against the outer faces thereof at points below the tread, and means on the tread for forcibly laterally distorting the rod intermediate its length the engagement of said means with the rod being'adapted to prevent the relative movement of each in a direction longitudinally of the rod.

2. In a ladder, the combination with a pair of side rails and an abutting tread therebetween having-its ends supported thereby and acting as a strut, of a tie rod extending through both side rails below the tread to react compressibly at its ends against the outer faces thereof at points below the tread, an intermediate portion of the rodbeing distorted upwardly adjacent to the underface of the tread, and a fixed eye on the underside of the latter locked with the said distorted portion of the rod to tension and prevent endwise movement, of the latter.

3. In a ladder, the combination with a pair of side rails and an abutting tread therebetween having its ends supported thereby and acting as a strut, of a tie rod extending through both side rails below the tread to react compressibly at its ends against the outer faces thereof at points below the tread, a washer on the underside of the tread, an intermediate portion of the rod being distorted upwardly to occupy the opening in the washer, a bolt extending through the tread having a head smaller than the washer opening provided with an eye engaging the distorted portion of the rod, and a nut on the upper side of the tread threaded on the bolt.

4. In a ladder, the combination with a pair of side rails and an abutting tread therebetween having its ends supported thereby and acting as a strut. of a tie rod extending through both side rails belowthe tread to react compressibly at its ends against the outer faces thereof at points below the tread, incompressible means on the underside of the tread having two points of engagement with an intermediate portion of the rod and a. rod distorting means on the tread engaging the rod between said points of engagement.

JOHN W. 'PEASE. 

